Olaf van der Spek wrote:
as the 200W 80 Plus Gold unit inside is only a small step behind a quality external power source.
Why can't internal PSUs be as good as or better than external ones?
Larry's statement should not be taken out of context -- or maybe he should have made it more explicit that the reference is to EFFICIENCY
only. There's a simple reason why the pico + adapter ends up more efficient at the <20W loads. The 200W stock PSU is well below its best efficiency range; maximum efficiency with most PSUs is reached at 50~70% of rated load. The <20W load is below the optimal range for the pico+Seasonic 80W 12VDC adapter, but not quite as much.
A class V AC/DC adapter is rated for maximum 87% efficiency (presumably at 50~70% of max load) while a Gold 80+ is rated for 90% at 50% load & 87% at full load. The picoPSU also has some losses through it -- the 12V line is passed straight through, but the 5V and 3.3V lines are converted from the 12V line, so there's always a loss. Perhaps as little as 5%, but this really means that even at its ideal, peak efficiency, the pico+adapter will always be lower than the 87% of the adapter alone.
If the Supermicro system was loaded up with its maximum hardware complement, and power load reached... say 60-70W or higher, the stock Gold 80+ PSU would likely draw LESS power (a watt or 2 or 3?) than the pico.
NOTE -- I will edit Larry's statement to clarify.